Dynamic Contention Window Adjustment for LAA Uplink Fairness
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Solution Overview
Problem
In Licensed-Assisted Access (LAA) systems, determining a proper contention window size for uplink transmission to ensure fair resource sharing and effective interference suppression in unlicensed spectra is challenging due to the presence of Wi-Fi devices, which causes radio signal interference and requires dynamic adjustment mechanisms.
Innovation Solution
A method and apparatus for determining contention window information, where a base station uses the receiving state of a reference subframe to adjust the contention window size and generate control signaling for user equipment (UE) to implement fair channel access through channel sensing based on random backoff, by increasing or decreasing the contention window size based on ACK/NACK feedback and preset thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed contention window size is used for LAA uplink transmission, then the channel access mechanism is simple, but fair resource sharing and interference suppression cannot be achieved
Solution Approach 1:
The patent applies dynamics by making the contention window size adjustable rather than fixed. The base station dynamically determines the contention window size for each uplink burst based on downlink reception status, allowing the system to adapt to varying channel conditions and achieve both simplicity in operation and effectiveness in resource sharing and interference suppression
Solution Approach 2:
The patent changes the parameter of contention window size based on downlink reception status. When downlink reception is good, a smaller contention window size is used; when reception is poor, a larger size is used. This parameter change enables the system to balance between access simplicity and interference suppression effectiveness
2Object-affected harmful factors
If the contention window size is increased to suppress interference, then collision interference is reduced, but channel access efficiency decreases
Solution Approach 1:
The patent dynamically adjusts the contention window size based on actual downlink reception conditions. The base station determines the appropriate size for each uplink burst, allowing the system to increase the window size only when necessary to suppress collision interference, while maintaining efficient channel access when interference is not an issue
Solution Approach 2:
The patent changes the contention window size parameter adaptively. The base station determines the size based on downlink reception status, increasing it only when collision interference is detected and maintaining smaller sizes otherwise, thus balancing interference suppression with channel access efficiency
3Reliability
If random backoff sensing is used for channel access, then fair resource sharing is achieved, but the complexity of determining proper contention window size increases
Solution Approach 1:
The patent uses feedback from downlink reception status to determine the contention window size for uplink transmission. The base station receives feedback about downlink reception quality and uses this information to determine the appropriate contention window size, simplifying the complexity of fair resource sharing while maintaining effectiveness
Solution Approach 2:
The base station acts as an intermediary that determines the contention window size based on downlink reception status. This intermediary role simplifies the complexity by centralizing the determination function at the base station, which has better knowledge of channel conditions, rather than requiring each UE to independently determine the optimal size
Data Source
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AI summary
Embodiments of the present invention provide a method for determining contention window information. The method includes: determining contention window information of a second uplink burst of UE according to a receiving state of a reference subframe; generating at least one piece of control signaling for scheduling at least one uplink subframe in the second uplink burst; and sending the at least one piece of control signaling to the UE. According to the method and an apparatus for determining contention window information in the embodiments of the present invention, the control signaling is sent to the UE, so that the contention window information of the UE can be adjusted, the UE can obtain an appropriate contention window, and fair channel access is implemented through channel sensing based on random backoff.